Conversion oil burner



Feb. 16, 1943. A. MACCHI CONVERS ION OIL BURNER Filed Feb. 24, 1940 FigJ.

Inventor Aldo Macchi,

HIS Attorney LGD Patente eh, H6, 1943 CONVERSION 01L BURNER Aldo Macchi,ileville, N. 3., assignor to General Electric Comny, a corporation ofNew York Application February 24, 1940, Serial No. 320,557

6 Claims. (Cl. 158-76) The invention relates to oil burners and theprincipal object is to provide an improved automatic electricallyoperated oil burner unit of the conversion type, which is fully enclosedso as to be quiet and clean and embodies an integral automatic flamedetector and control so that the unit may be readily applied to varioustypes of furnaces or boilers.

A specific object is to provide an improved conversion oil burner nozzlewith an improved form of integral automatic flame detector and with animproved form of base and enclosing casing construction wherebysubstantially standard and separate burner and automatic control partscan be unified and electrically interconnected in cooperating relationthereby insuring that all parts of the unit work properly together andfacilitating the proper installation, and servicing of the unitirrespective of the type of furnace or boiler to which the unit isapplied.

' A more specific object is to provide an improved conversion oil burnerconstruction having an adjustable base pan and upright wall. mountingstructure with a complementary removable enclosing jacket or cover forthe electric motor driven air and oil upply mechanism, and the automaticelectric control parts or the unit, and with the nozzle and flamedetector control parts, which must project into the furnace, removablyconnected to the wall in proper operating relation with the other parts.This improved mounting and enclosing structure protects the electricaland the oil and air supply mechanism from the nozzle heat, provides forquiet, clean and emcient operation, enables the burner nozzle height tobe readily varied by raising or lowering the base pan and wallindependently of the jacket to conform with the height of the furnacedoor opening and also enables all the principal parts of the unit to bereadily accessible upon removal of the cover for inspection, repairs,removal or replacement, without disturbing the main burner nozzle tubeafter it is once sealed in its proper position in the refractory wallsof the furnace combustion chamber.

Another object of the invention is to provide an improved air injectionconstruction ad- Jacent the end of the conversion burner nozzleextending into the combustion chamber for receiving an integralautomatic flame detector, whereby a quick and reliable response oi theautomatic flame detector control is obtained without subjecting thetemperature responsive parts to excessive or destructive temperatures.To meet the Patent Ofice requirements my. divi-- height.

sional application Serial No. 440,378 was filed April 24, 1942, withclaims to this feature.

A further object is to provide an oil burner having a very low nozzletip temperature during the running period as well as after shut down ofthe burner operation. This low tip temperature prevents the forming oftarry or carbon residues in the nozzle, thus avoiding the tendency forsuch residues to slowly accumulate and clog the nozzle parts.

Other objects will appear in the following description of theaccompanying drawings illustrating preferred embodiments of theinvention and in which Figure 1 is a side view partially in section ofan automatic electrically operated conversion oil burner unit providedwith the improvements of the present invention; Fig. 2 is a top viewpartially in section of theoil burner unit shown in Fig. 1, and Fig. 3is an end view of the burner nozzle showing the improved location of theimproved flame detector control part adjacent the end of the nozzle.

As shown in Fig. 1 the conversion oil burner unit comprises a base itwith the adjustable legs I I upon which base are mounted all of theprincipal operating and control parts of the conversion oil burner unitincluding the electric motor driven air blower and air and oil pumpingmechanism I2, the high voltage electric ignition transformer It, theautomatic starting, stopping and sequence timing control mechanism It aswell as the complete burner air and oil discharge nozzle assemblage itincluding the main combustion air discharge nozzle Ilia which is adaptedto be sealed into the refractory wall I6 01 a boiler furnace or othertype of furnace to which the conversion oil burner unit is applied andthe oil atomizing nozzle 2i and other parts which are mounted inside ofthe main nozzle lta. The three supporting legs H are threaded into thebase it so as to be independently adjustable, thereby permitting theentire burner nozzle assemblage E5 to be raised or lowered to the properheight from the floor upon which the unit is mounted to conform with thefurnace combustion chamber and also permitting leveling of the unit atthe desired The base it preferably is of pressed metal formed into theshape of an oil or drip pan as shown in the drawing.

The motor driven mechanism it constitutes the electric motor drivenoil'and air pressure supply means for theburner nozzle assemblage it andpreferably is of the improved type described and claimed in the LumPatent 2,032,291,

granted February 25, 1936, although any other suitable type ofcombustion air blower and atomizing air and oil pumping means may beprovided for supplying the burnernozzle IS with oil and combustion air.The motor driven mechanism |2 preferably is resiliently mounted upon thebase ID by means of suitable springs |1 so as to avoid transmission ofnoise and vibration to the base.

The electric ignition transformer I3 is shown as of the conventionaltype with its high voltage terminals l8 connected through suitableconductors l3 to produce an are between the two spaced apart ignitionelectrodes 20 which are located inside the combustion air nozzle lie andabove and closely adjacent to the end of the oil atomizing nozzle 2| soas to ignite the atomized oil stream discharged therefrom into thecombustion air stream discharged from nozzle I611. The

oil 'atomizing nozzle 2| preferably is of the improved constructionillustrated and described in my copending application, Serial No.320,558,- filed concurrently herewith.

The proper energization of the ignition transformer I3, theelectromagnetically operated oil flow control valve 22, and also theelectric motor driven air and oil pumping mechanism |2 from a suitablesource of electric power are under the control of a suitable oil burnertiming sequencing control switch mechanism ll which may be of anydesired type although preferably it is of the type which is describedand claimed in the Eaton Patent No. 2,134,550, granted October 28, 1938.The various control details are well known in the art and are not deemedessential to proper understanding of the present invention and hence arenot shown other than the transformer |4a for energizing the usual lowvoltage room thermostat control circuits and the control motor Ilb foroperating suitable sequencing cam switch mechanism for coordinating theenerg'ization of the proper burner control circuits at proper times, inconjunction with the flame detector switch mechanism 50 which isdescribed in more detail hereinafter.

As shown in Figs. 1, 2 and 31, the burnercombustion air supply nozzle|5a preferably is mouid ed of cast iron and provided with suitablemounting lugs 25 so that it may be detachably mounted upon the uprightwall 26 which extends upward- 1y from the right-hand end of the base l0and is suitably secured thereto as by spot welding. The removable jacketor enclosing casing 21 for the unit cooperates with the upright wall 26to enclose all of the operating parts of the oil burner unit except thenozzle assemblage IS on the outside of the wall. The upright wall 26 isprovided with suitable openings for receiving the bolts 28 whichdetachably mount the main combustion air nozzle I50. within which allthe other nozzle parts are mounted.

The upright wall 26 has suitable openings formed therein through whichextend the oil supply pipe 29 and the air supply pipe 30 whichinterconnect the inner oil atomizing 'nozzle 2| with the air compressorand oil pump of the motor driven mechanism l2. As shown these oil andair supply pipes 29 and 36 extend through the nozzle tube 3| which ismounted along the axis of the main combustion air nozzle i511. andadjacent the end of which the oil atomizing nozzle 2| is mounted. Thenozzle tube 3| also carries the supporting bracket 32 in which theignition electrodes are mounted in proper spaced relation with theatomizing nozzle 2| to effect ignition of the atomized oil streamdischarged therefrom. A suitable combustion air whirler or spinner 33 ismounted upon the nozzle tube 3| with the ends of the blades thereofextending into sliding engagement with the interior of the combustionair nozzle |5a adjacent the discharge end thereof. Thus the'spinner 33serves to maintain the nozzle tube 3| centrally at the axis of nozzle.l5a.

The oil and air supply pipes 23 and 30 are suitably secured to aremovable mounting plate 34 which is removably mounted in spaced apartrelation with the removable mounting plate 34a to which tube 3| issecured so as to permit a flow of air through the nozzle tube 3| frominside the enclosing jacket 21 due to natural draft and of the burnerunit is obtained by allowingsome fan air to enter the tube 3| throughthe hole 3|a which is located in tube 3| so that the air flow resistance(Fig. 1) ofiered by the air spinner 33 will cause some combustion air toenter tube 3| through hole Ma.

The upright wall 26 also is provided with another suitable openingadjacent the top thereof for transmitting air under pressure from themotor driven blower 36 to the inside of the enlarged offset air inletscroll casing portion 36 of the combustion air nozzle IS the open end ofwhich is closed by the wall 26. The pressure of the air supplied fromblower 35 is regulated by means of a suitable adjustable damper 35alocated adjacent the blower inlet. As shown in Figs. 1 and 3 theenlarged offset air inlet scroll casing portion 36 of the air nozzle l5forms in conjunction with the sealing upright wall 26 a flow directingchamber 36a for directing the combustion air flow downwardly andimparting a slight rotating motion thereto upon the entrance of the airunder pressure to the nozzle l5. This enlarged offsetscroll portion 36of the air nozzle l5 distributes the combustion air coming from theblower 35 through chamber 360. so that it flows in equal amounts betweenthe three equilaterally spaced fixed baffles 361) thereby improving thestability of the flame. The converging air discharge tip |5b of thecombustion air nomle l6 preferably is made removable so that the tip libmay be replaced whenever required as for example in case an extension ofthe air and oil nozzles should become necessary for properly installing'the conversion oil burner unit in a large size warm air furnace. Theenlarged oi!- set scroll portion 36 of the air nozzle |5a serves tointercept much of the direct radiant heat from the furnace combustionchamber and transmit such heat to the air flowing into the air nozzlel5a. thereby improving the combustion eiiiciency and at the same timepreventing overheating of the operating part of the burner unit locatedbehind the wall 26 within the enclosing jacket or casing 21 closelyadjacent the combustion chamber.

The air flow connection from the scroll housing of the blower 35 intothe combustion air inlet opening 31 formed in the upright wall 26preferably is made flexible and resilient by means of a suitable feltbushing 38 which is enclosed within the bushing mounting casing 39 whichin turn is removably mounted upon the upright wall 26 in any suitablemanner. The flexible felt bushing 33 prevents transmission of mechanicalvibration from the electric motor driven blower compressor mechanism i 2to the wall 26 and also serves to prevent leakage of the air underpressure in its passage from the blower housing 35 into the flowdirecting chamber 36a.

The upright wall 2% also is provided with a suitable opening formounting the detachable coupling 68 of the oil supply pipe 40a. CouplingM3 is connected through the flexible looped pipe at with the intake port#32 of the oil pump embodied in the electric motor driven oil and airmechanism i2.

With the improved conversion oil burner unit construction as abovedescribed it will be observed that all of the main operating parts ofthe burner are readily detachable from the cast iron air nozzle [5aafter it is once sealed in proper operating condition in the furnacecombustion chamber as illustrated in Fig. 1. By loosening the mountingbolts 2! and disconnecting the oil supply .pipe 60a and the electricpower supply and control cable 42, the entire unit including the baseit, upright wall 26 and all the parts mounted thereon, and alsoincluding the nozzle 2!, the inner nozzle tube at, and electrodes 20 maybe moved as a unit to the left and thereby detached entirely from thecombustion air nozzle l5. This facilitates ready inspection, replacementor repair of all of the operating parts of the burner unit. Furthermore,by merely lifting the enclosing jacket 2? which rests upon its bottomedge upon the floor entirely independently of the main supporting base10, all of the main essential operating parts of the burner and controlmechanism are made readily available justment or replacement.

As shown in Fig. 2 the opposing upright edges 45 of the removableenclosing jacket 27 extend in overlapping sliding relation with theopposite side edges of upright wall 26. Thus when the base it isadjusted to its maximum height so as to bring the upper edge of wall 28into overlapping sliding engagement with jacket 27 as shown in Fig. 1then all combustion air is drawn into the blower air intake opening 35ainside of the" enclosing jacket 27 after passing between the opposingupright edges 45 of the jacket 2'! and under the base ID from theright-hand side of the enclosing jacket closely adjacent the furnacecombustion chamber as indicated by the arrows in Fig. 1. In case thebase It should be lowered so as to decrease the area of the air inletopening extending between the opposing upright edges 45 of the enclosingjacket 21 below the base It then an equivalent area of air inlet openingis obtained above the top of the wall 26. Hence the necessary air inletarea into the jacket 21 isobtained irrespective of the height at whichthe base i0 is mounted. In any case the air inlet opening into jacket 21is directly adjacent the furnace combustion chamber so as to drawtherein any heated air, fumes or products of combustion that may bereleased from the furnace. This location of the air inlet opening intojacket 27 also serves to suppress the transmission of noise from theinside of the enclosing .casing 21 to the surrounding atmosphere sinceany noise vibrations which may pass through the air inlet opening areintercepted by the furnace.

The improved burner unit construction described above provides formaximum freedom in the construction, size and location of the variousessential elements of the burner air and oil supply and ignitionmechanism mounted upon the base it without interference with the othercoopfor repair, ad-

crating elements. Each main essential element may be separatelymanufactured in a standard form or size and mounted independently of theothers but in proper spaced and cooperating relation therewith. Thispromote improvements in the structure of the severalelements andfacilitates the final interconnection thereof in proper cooperatingrelation in the improved conversion oil burner unit. Any one of thevarious essential elements may be improved in structure with a minimumof interference with the other elements.

In the preferred form of the invention illustrated in the drawing, theautomatic burner control mechanism It is shown mounted directly upon theupright supporting wall 26 with the flame responsive switch mechanism 56preferably constructed as an integral part of the main automatic controlIt and arranged to be responsive to combustion conditions immediatelyadjacent the end of the burner nozzle. It will be understood, however,that the flame responsive switch mechanism may be made a 'separateelement from the main automatic sequencing control switch mechanism Itif desired. In the form shown in Fig. 2 the flame responsive switchmechanism comprises a base plate 5| to which is attached the supportingbracket 52 carrying the pivoted switching arm '53 having the contact 54carried at the end thereof between the two cooperating contacts 55 and56. The pivoted switch arm 53 is biased by spring 57 to engage contact54 with operated against the bias of spring 51 by the contact 68. Thepivoted switch arm 53 is the sliding pin 58 which is connected throughthe agency of the quartz rod 59 which is relatively non-expansible upontemperature changes with the temperature responsive expansive tube 50.The temperature responsive expansive tube 66 preferably is formed ofnichrome or other suitable high temperature expansible material and ismounted at the end of the supporting tube at which extends through theair inlet casing 35 and in turn is supported from the base plate 5! Theburner combustion air nozzle nozzle I5 is provided with a specialauxiliary housing 15 extending from one side thereof adjacent thedischarge end of the nozzle. into the combustion chamber of the furnace.{This special auxiliary housing 15 is formed with a substantially U-shaped internal passageway 750. with bolts ends of the U-shaped passageopening directly into the furnace combustion chamber as indicated moreclearly in Figs.'2 and 3. In one leg it oi this internal U-shapedpassageway 15a, the temperature responsive expansible element 60 of theflame detector is located. A small auxiliary air supply nozzle Ti isconnected with the laterally ofiset scroll portion 36 of the combustionair supply nozzle I5 so as to admit a jet of air under pressure from thescroll portion 36 into the other leg 18 of the U-shaped passage the.Thus the jet of air under pressure issuing team the nozzleit into thepassage it sets up an injector action which produces a circulation ofthe products of combustion from the combustion chamber through theU-shaped passage itself and back again to the furnace combustionchamber. In this way a flow of the products ofcombustion from thefurnace combustion chamber is drawn by the injector action set up by theauxiliary air nozzle ll over the temperature responsive tube element 60of the flame detector. Thus the element 68 although located entirelyoutside the furnace combustion chamber is made directly responsive tothe temperature conditions produced by combustion in the furnacewhenever the blower 85 isoperating to supply air under pressure to theinjector nozzle 11.

=Whenever the oil burner unit is started into operation by means of thesuitable automatic control mechanism I which ordinarily is under thecontrol of a room thermostat or other automatic condition responsivecontrol, oil and air will be supplied under pressure from the motordriven oil and air supply mechanism H to the burner atomizing nozzle 2|.At the same time combustion air under lower pressure will be suppliedfrom the blower 35 to the inlet 31 of the combustion air nozzle l5. Thisflow of combustion air passes along and cools the outside of the nozzletube 3| within which the oil atomizing nozzle 2| is mounted. Also afurther cooling air flow is drawn through the inside of the nozzletubeSl directly over the oil atomizing nozzle 2|. This cooling air flowthrough the inside of the nozzle tube 3| is jointly dependent upon theinjector action produced by the blower air flow at the tip of nozzle l5and also upon the natural draft produced by the furnace. Hence thecooling air flow through the inside of nozzle tube 3| will continueindependently of the operation of blower 35 and prevent overheating ofnozzle 2| when the burner unit is shut down.

When the atomized oil stream issuing from the nozzle 2| is ignited from.the electric arc established between the electrodes 20, combustionnormally will be established within the furnace combustion chamber. Thearcing electrodes are energized from the high voltage terminals of theignition transformer Hi, the primary of which is suitably energizedduring the proper interval by the operation of the sequencing timingcontrol mechanism l4.

Due to the injector action produced by the auxiliary air nozzle 11, someproducts of combustion will be drawn from the furnace combustion chamberover the temperature responsive expansible tube 60 thereby producing amovement of the flame responsive switch arm 53 to indicate the presenceof combustion in the combustion chamber. In case combustion shouldthereafter fail, the tube 60 wil1 cool thereby reversing the operationof the switch arm 53 to in-- dicate the absence of combustion. It willbe understood that the flame detector switch 50 is intended to cooperatewith the burner control mechanism It so as to shut down the motor drivenoil and air supply means in case of combustion failure in the mannerwhich is well known in the art. Likewise the flame detector switch 50will cooperate with the control mechanism It to prevent continuedoperation of the motor driven compressor mechanism l2 in case combustionis not established within a limited time interval after the burner unitis started into operation. This prevents accumulation of unburned oil inthe combustion chamber which might result in puffs, explosions or otherdangerous conditions.

With the improved conversion burner unit construction described above,the flame detector 5!! and control mechanism It forms an integral partof the unit and hence materially simplifies the installation problem.All of the various cooperating parts may be properly mounted,interconnected in the proper cooperating relation and tested together.Thus all that is necessary for installation is to seal the burner airnozzle l5 in the furnace combustion chamber and provide the necessaryoil and electric power supply and control connections to the unit.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. In an oil burner unit, in combination, a drl pan having adjustablesupporting legs extending from the bottom thereof, and having an uprightwall at one side thereof, electric motor driven oil and air supply meansremovably mounted upon said pan, burner means connected with said supplymeans including an oil discharge nozzle and av combustion air dischargetube carried by said wall and provided with means for removably mountingsaid nozzle through said wall inside said tube and an independentlysupported removable cover having an opening with the edges thereofslidably engaging said wall for enclosing said air and oil supply meansand providing a constant area air inlet thereto independently of theadjustment of said legs.

2. In an oil burner unit, in combination, an adjustable supporting baseincluding a drip pan having an upright wall at one side thereof,electric motor driven oil and air supply means removably mounted uponsaid drip pan, 9. removable jacket cooperating with said wall forenclosing said supply means, and burner means connected with said supplymeans including an oil discharge nozzle and a combustion air dischargetube carried by said wall and provided with means for removably mountingsaid nozzle through said wall inside said tube,

3. In an oil burner unit, in combination,- a supporting baseprovided'with adjustable legs for leveling the base at varying distancesabove a floor level, an independently floor mounted jacket surroundingsaid base and provided with an air inlet opening at the bottom thereof,electric motor driven oil and air supply means mounted on said basewithin said jacket and including a blower provided with an air inletopening inside said jacket and a burner nozzle removably mounted on saidbase and having oil and air passages removably connected with said alland air supply means. a

4. In an oil burner, in combination a combustion air discharge nozzleadapted to be mounted in the wall of a furnace combustion chamber andhaving a lateral air supply scroll casing at one end thereof providedwith a removable wall extending transverse the axis of said nozzle andwith an air inlet opening offset from the axis of said nozzle formed insaid wall, an oil supply pipe mounted in said removable wall for removalas a unit therewith and extending within said air nozzle and having anoil nozzle at the end thereof for discharging an atomized stream of oilalong the axis of said air nozzle adjacent the discharge end thereof andelectric motor driven oil and air supply means connected with saidremovable wall for removal as a unit therewith, said supply meansincluding an air blower discharging into said offset air inlet openingformed in said wall and an oil pump for supplying oil under pressure tosaid oil supply pipe.

5. In an oil burner, in combination, a supporting base plate havingadjustable legs extending from the bottom thereof and having an uprightwall at one side thereof, an air discharge nozzle tube carried by saidwall and having casing means abutting said wall to form a lateral airinlet chamber for said tube, an oil discharge nozzle removably mountedwithin said tube adjacent the discharge end thereof, motor driven oiland air supply means removably mounted upon said base plate and having aremovable oil supply conduit extending through said casing means andsaid air nozzle tube to supply oil to said oil discharge nozzle andhaving an air supply conduit removably connected with said air inletchamber,

and a. removable Jacket cooperating with said wall for enclosing saidsupply means.

6. In an oil burner, in combination, an adjustable height base platehaving an upright wall at one side thereof, burner means including an 10motor'driven oil and air supply means mounted' on said base including anoil pressure supply means connected with said oil supply conduit and ablower connected with said air inlet chamber.

ALDO MACCHI.

